JPH115158A - Jointing and brazing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always feed a proper amount of brazing filler member to a jointing part by calculating a feature volume for the area based on an image signal received/converted from a specular reflected light in the jointing member melting area, and by stopping the feed of the jointing member and evacuating the member when the feature volume reaches the tolerance value. SOLUTION: A brazing objective work 10 is carried into a brazing position and, a position of the brazing unit 5 is decided by the control of the brazing member feeding volume control unit 9. A neighboring area of the brazing objective work 10 is pre-heated by a burner flame. When a surface temperature measured by a radiation thermometer is judged to be higher than the temperature threshold value, the general control unit 4 issues an order to the brazing member feeding control unit 9 to feed a brazing core wire to the jointing part. An ACCD camera of a measuring unit 6 catches an image signal based on the reflected light from the mirror face of the jointing part and converts it to calculate the feature volume of the brazing fusion area and the like. When the feature volume exceeds the threshold value, the brazing member feeding control unit 9 stops the feeding of the brazing member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to various brazing methods such as torch brazing, high frequency brazing, electric resistance brazing, that is, soldering when the melting point of the joining material is 450 ° C., and the name is changed to brazing. Relates to a joining method and a brazing method including these.

[0002]

2. Description of the Related Art There are the following two systems for supplying a brazing material. A brazing method in which a brazing material is supplied in advance in the vicinity of a joining portion of a member to be joined, and a brazing material core wire is sequentially supplied to the joining portion when the temperature of a material having good wettability is reached after the member to be joined is preheated. There is a method. In the case of the brazing method, the brazing material supply amount is obviously only a fixed amount supplied in advance, and is not added during heating. In the case of the brazing method, the brazing material supply amount is variable by controlling the brazing material supply time or the brazing material supply speed.

As a conventional measurement control method for brazing, an example using a position measurement of a member to be joined and a temperature measurement for confirming good wettability as disclosed in JP-A-6-246436 is well known. Have been. In these conventional examples, after the member to be joined is installed in the apparatus, the relative positioning between the torch, the brazing material supply mechanism and the member to be joined is performed, and preheating is performed. After confirming that the temperature in the vicinity of the joint of the members to be joined has reached a temperature with good wettability by the temperature measuring means, the brazing material supply is started, and heating is stopped when the brazing material is supplied for a certain time, and brazing is performed. Complete.

[0004] As an example of the measurement of the brazed molten region at the joint to be welded, several examples relating to a brazing method have been known. In the brazing, a fixed amount of brazing material is supplied to the joint in advance, and in the case of solder, cream solder is already supplied, and the brazing material installation position is clear. In this case, Japanese Patent Application Laid-Open No. Sho 63-30937
1, JP-A-6-297141, JP-A-7-270239
There has been known an invention which estimates a molten state of a wax using an image in an infrared region as shown in Japanese Patent Application Laid-Open No. H11-157572. This measures the temperature of the brazing material itself by detecting electromagnetic waves radiated from the brazing material itself during heating, so-called radiant heat, estimates the melting state of the brazing material, and when the brazing material reaches a preset temperature, the brazing material is Judging that it had melted and infiltrated, heating was stopped and brazing was completed. This method can be used only when the supply position of the brazing material to be measured is clear.

However, in the case of brazing, since the position of the brazing material is unknown, it is necessary to perform separation recognition of the melting region of the brazing material from the background image such as the surface of the member to be joined. As a measure against this,
Japanese Patent Application Laid-Open No. Hei 7-88639 is known in which a technique similar to the placing method is applied to a solid-state imaging device capable of surface measurement. This raises the temperature of the surface of the member to be joined as well,
Since the emissivity differs between the surface of the member to be joined and the brazing material melting region, the brazing melting region is separated and recognized based on the image in the infrared region based on the emissivity. It has been proposed that the separated and recognized area of the brazing molten region is fed back to the brazing material supply control function to control the brazing material supply amount, and is known as a measure against the shortage of the brazing material at the joint due to dripping. .

[0006]

In the prior art described above, when electromagnetic waves, so-called radiant heat, radiated from the brazing material itself are actually detected by the image pickup device, the luminance B observed by the image pickup device is expressed by the following equation (1). ), Is obtained by a monotone increasing function f of the product of the actual temperature T and the emissivity α.

B = f (T × α) (Equation 1) For this reason, the product T is defined as the luminance B observed in the solid-state imaging device.
When the value of α is equal, the brightness becomes the same irrespective of the brazing fusion region and the surface of the member to be joined, so that separation recognition is impossible. Also, in the infrared region, since the reflected image of some light source (light amount: L) is measured simultaneously with the radiant heat, the luminance B is expressed by the light amount L and the reflectance β as shown in the following equation (2). Is obtained by a monotonically increasing function g including a product term of. B = g (T × α, L × β) (Equation 2) In this case, the light source is not only disturbance light such as sunlight or a building ceiling light, but also burner light in the case of torch brazing. As described above, in the prior art, it is very difficult to separate and recognize the brazing molten region, and as a result, even in the case of brazing, it is difficult to properly supply the brazing material to the joints. I was Further, in the prior art, in the case of brazing, after a nozzle for sending a brazing filler metal wire is brought close to a portion to be joined, a brazing filler metal wire is ejected from the nozzle by about several mm due to an external flame of a burner with a delay time. Because it is sent out after preheating, the brazing material core wire is supplied to the portion to be joined and breaks through the member to be joined in a state where the delay time is short and is not sufficiently preheated, or the member to be joined is bent, Further, if the delay time is too long, the brazing material melts down before reaching the portion to be joined and is not supplied, so that setting and managing the delay time is extremely difficult.

[0008] An object of the present invention is to solve the above problems.
The brazing material is supplied to the part to be welded and the molten region of the brazing material melted can be separated and recognized from the part to be welded, so that an appropriate amount of brazing material is always supplied to the part to be welded so that reliable joining can be realized. It is an object of the present invention to provide a joining method and a brazing method which have been described. Another object of the present invention is to provide a brazing method in which an appropriate amount of brazing material is always coated by allowing the brazing material melted region supplied to the portion to be welded to be melted and separated from the portion to be welded. An object of the present invention is to provide a joining method and a brazing method that can be supplied to a joining portion to realize a highly reliable joining. Another object of the present invention is to
In the brazing method, the brazing material melted region where the brazing material is supplied to and melted from the portion to be welded can be separated and recognized from the portion to be welded. It is an object of the present invention to provide a joining method and a brazing method capable of always supplying an appropriate amount of brazing material to a portion to be joined and realizing a highly reliable joining even when a gap interval is different and a brazing material penetration amount is changed. is there.

[0009]

In order to achieve the above object, the present invention provides a method for heating the vicinity of a portion to be welded between members to be welded by a heating means so that the heated surface temperature of the portion to be welded becomes a desired temperature. Is measured by the temperature measuring means, and based on the measured signal, the bonding material is sent to the bonded portion, and the tip of the bonding material is pressed against the bonded portion in a reducing action state with a desired force. Thereby, the joining material is melted by the surface temperature of the joined portion, and the image is formed by irradiating the joined portion in the reducing action state with light and receiving an image by mirror reflection light from the joining material melting region by the photoelectric conversion means. Convert it to a signal,
Based on the converted image signal, a characteristic amount indicating the fusion region of the bonding material is calculated. When the calculated characteristic amount reaches an allowable value, the feeding of the bonding material to the portion to be bonded is stopped, and then the bonding is performed. A joining method, wherein a material is retracted from the joined portion. Further, according to the present invention, the vicinity of the portion to be joined between the members to be joined is heated by the heating means, and the temperature of the heated surface of the portion to be joined becomes a desired temperature is measured by the temperature measuring means. The joining material is sent to the joining portion based on the above, and the tip of the joining material is pressed against the joining portion in a reducing action state with a desired force to melt the joining material by the surface temperature of the joining portion, and The part to be joined in a reducing action state is irradiated with light to block light components due to radiant heat obtained from the part to be joined, and an image by mirror-reflected light from a fusion region of the joining material is received by the photoelectric conversion means, and an image signal is received. Is calculated based on the converted image signal, and calculates a characteristic amount indicating the fusion region of the bonding material. When the calculated characteristic amount reaches an allowable value, the feeding of the bonding material to the portion to be bonded is stopped. , And then the bonding material Serial is a joining method characterized by retracting from the welded portion.

[0010] The present invention is also characterized in that in the joining method, the joining material is a solder material. Further, the present invention is characterized in that in the joining method, the joining material is a brazing material. Further, in the present invention, the vicinity of the portion to be bonded between the members to be bonded is heated by heating means, the bonding material is supplied to the portion to be bonded in a reducing action state, and the bonding material is melted by the surface temperature of the portion to be bonded, By irradiating light to the part to be joined in the reducing action state, the image by the mirror reflection light from the bonding material melting area is received by the photoelectric conversion means and converted into an image signal, and based on the converted image signal, the bonding material is used. A joining method is characterized in that a feature amount indicating a fusion region is calculated, and when the calculated feature amount reaches an allowable value, the supply of the joining material to the portion to be joined is stopped. In the present invention, the vicinity of the portion to be bonded between the members to be bonded is heated by a heating unit,
The bonding material is supplied to the bonded part in the reducing operation state, the bonding material is melted according to the surface temperature of the bonded part, and the bonded part in the reducing state is irradiated with light to be obtained from the bonded part. A light component due to radiant heat is shielded, and an image based on specular reflection light from the bonding material melting region is received by a photoelectric conversion unit and converted into an image signal, and a characteristic amount indicating the bonding material melting region based on the converted image signal. Is calculated, and when the calculated feature value reaches an allowable value, the supply of the bonding material to the portion to be bonded is stopped.

Further, according to the present invention, the vicinity of a portion to be welded between the members to be welded is heated by a burner flame, and the surface temperature of the heated portion to be welded is measured to be a desired temperature by a temperature measuring means. The brazing material is sent to the portion to be welded based on the received signal, and the tip of the brazing material is pressed against the portion to be welded in the reducing atmosphere with a desired force to melt the brazing material according to the surface temperature of the portion to be welded. Then, light is irradiated to the portion to be joined in the reducing atmosphere, an image by the mirror reflection light from the brazing material melting region is received by the photoelectric conversion means, converted into an image signal, and based on the converted image signal. Calculating the characteristic amount indicating the brazing material melting region, and when the calculated characteristic amount reaches an allowable value, stops sending out the brazing material to the portion to be joined, and then retracts the brazing material from the portion to be joined. The feature is to let That is a bonding method. The present invention also provides
The vicinity of the portion to be welded between the members to be welded is heated by a burner flame, the surface temperature of the heated portion to be welded is measured by a temperature measuring means to reach a desired temperature, and a brazing material is used based on the measured signal. And the tip of the brazing material is pressed with a desired force against the to-be-joined part in the reducing atmosphere to melt the brazing material by the surface temperature of the to-be-joined part. A photoelectric conversion means for irradiating light to the part to be welded and blocking an optical component due to a burner flame obtained from the part to be welded and a light component due to a flame color reaction of the brazing material to convert an image by mirror-reflected light from a brazing material melting region. And converts it into an image signal, calculates a feature amount indicating a brazing material melting region based on the converted image signal, and, when the calculated feature amount reaches an allowable value, the joined portion of the brazing material Stop sending to A brazing method for causing thereafter retracting the brazing material from the bonding portion.

Further, according to the present invention, the vicinity of a portion to be welded between members to be welded is heated by a burner flame, and the surface temperature of the heated portion to be welded is measured to be a desired temperature by a temperature measuring means. The brazing material is sent to the portion to be welded based on the received signal, and the tip of the brazing material is pressed against the portion to be welded in the reducing atmosphere with a desired force to melt the brazing material according to the surface temperature of the portion to be welded. And irradiating light to the part to be joined in the reducing atmosphere to light the light component due to the burner flame and the light component due to the flame color reaction of the brazing material and the light component due to the radiant heat obtained from the part to be joined. The image by the specular reflection light from the fusion region is received by the photoelectric conversion means and converted into an image signal, and a characteristic amount indicating the brazing material fusion region is calculated based on the converted image signal, and the calculated characteristic amount is calculated. Is acceptable Stop feeding to the joined portion of the brazing material when it reaches a subsequent brazing process, characterized in that retracting the brazing material from the bonding portion.
Further, in the present invention, the vicinity of the portion to be joined between the members to be joined is heated by a burner flame, the brazing material is supplied to the portion to be joined in a reducing atmosphere, and the brazing material is melted by the surface temperature of the portion to be joined. By irradiating light to the joints in the reducing atmosphere, the image by the mirror reflection light from the brazing material melting region is received by the photoelectric conversion means and converted into an image signal, and based on the converted image signal, the brazing material is used. Calculate the characteristic amount indicating the melting area,
A brazing method characterized in that the supply of the brazing material to the portion to be joined is stopped when the calculated feature amount reaches an allowable value.

Further, according to the present invention, the vicinity of the portion to be welded between the members to be welded is heated by a burner flame, and the brazing material is supplied to the portion to be welded in a reducing atmosphere so that the brazing material is melted by the surface temperature of the portion to be welded. Irradiating light to the portion to be joined in the reducing atmosphere to shield a light component due to a burner flame obtained from the portion to be joined and a light component due to a flame color reaction of the brazing material to a mirror surface from the brazing material melting region. The image due to the reflected light is received by the photoelectric conversion means and converted into an image signal, and a characteristic amount indicating the brazing material melting region is calculated based on the converted image signal, and the calculated characteristic amount reaches an allowable value. Then, the supply of the brazing material to the portion to be joined is stopped. Further, in the present invention, the vicinity of the portion to be joined between the members to be joined is heated by a burner flame, the brazing material is supplied to the portion to be joined in a reducing atmosphere, and the brazing material is melted by the surface temperature of the portion to be joined. By irradiating light to the part to be joined in the reducing atmosphere, the light component due to the burner flame and the light component due to the flame color reaction of the brazing material and the light component due to radiant heat obtained from the part to be joined are shielded from the brazing material melting region. The image by the specular reflection light is received by the photoelectric conversion means and converted into an image signal, and a characteristic amount indicating the brazing material melting region is calculated based on the converted image signal, and the calculated characteristic amount is an allowable value. , The supply of the brazing material to the portion to be joined is stopped. The present invention also provides
It is characterized in that a burner flame made of oxygen-propane or the like is used as the heating means, and an upper limit value of a wavelength range received by the photoelectric conversion means is 590 nm or less. Further, in the present invention, as a lighting means for irradiating light, a multi-stage lighting using a ring-shaped fluorescent lamp is employed.

As described above, according to the above configuration,
Since the part to be joined is always in a reducing action state, that is, in a reducing atmosphere, in order to remove the surface oxide film, the brazing fusion region is always in a mirror state, and the emissivity α is small in this mirror surface part. Focusing on the fact that the reflectance β increases,
The brightness of the reflected image is received by the photoelectric conversion means, converted into an image signal, and the amount of characteristic (the area, the length in the horizontal direction, and the length in the vertical direction) of the image signal is calculated to separate the molten solder region. By recognizing, even if the gap distance between the members to be joined is different due to the variation in the dimensions of the parts or the difference in the fitting state, the permeation amount of the brazing material changes, always supplying the appropriate amount of the brazing material to the parts to be joined. It is possible to realize highly reliable bonding. Further, as in the above configuration, after the pre-heating of the part to be joined, the brazing material is sent out to the part to be joined, and the tip of the brazing material is pressed against the part to be joined in the reducing atmosphere with a desired force. Since the brazing material is melted by the surface temperature of the solder, it is possible to always supply an appropriate amount of the brazing material to the portion to be welded, thereby realizing highly reliable joining.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a joining method, a brazing method, and a device according to the present invention will be described with reference to the drawings. As a brazing method according to the present invention, a copper pipe fitted to a member to be joined and a case of brazing using a phosphor copper brazing material as a brazing material will be described.
Although the case of torch brazing with oxygen-propane is shown here, the present invention is also effective in the case of high-frequency induction heating or the like as a heating method. First, a brazing method according to the present invention will be described with reference to FIGS. FIG.
1 is a schematic configuration diagram showing one embodiment of a brazing apparatus according to the present invention. This is based on a three-axis orthogonal robot mechanism 1, a gantry 2, a robot controller 3, an image processing device and an overall controller 4, a brazing unit 5, a measuring unit 6, a gas flow controller 7, and a ring-shaped fluorescent lamp. It is composed of a multi-stage illumination 8 and a work 10 to be brazed (member to be joined) made of a fitted copper pipe. Work to be brazed (member to be joined) 10 consisting of a fitted copper pipe
Is conveyed manually or automatically (such as a conveyor) and positioned at a brazing position. The multi-stage illumination 8 using a ring-shaped fluorescent lamp is installed above the brazing position where the work 10 to be brazed (member to be joined) is positioned. The three-axis orthogonal robot 1 is set on the gantry 2,
The brazing unit 5 and the measuring unit 6 are arranged on the end effector. That is, the brazing unit 5 and the measuring unit 6 move and move in the three axes by the three-axis orthogonal robot mechanism 1 based on the control from the robot controller 3.
Workpiece to be brazed by welding (member to be joined) 10
It is configured so that it can be positioned with respect to. Further, the image signal measured by the measuring unit 6 and information on the surface temperature of the portion to be joined are input to a processing device for images and the like and to the overall control device 4. Further, the robot controller 3, the brazing material supply amount controller 9, and the gas flow controller 7 are controlled based on control commands from a processing device for images and the like and the overall controller 4. The robot control device 3, the brazing material supply amount control device 9, and the overall control device 4 may be configured by one control device.

FIG. 2 shows the brazing unit 5 shown in FIG.
FIG. 3 is an enlarged perspective view showing a specific configuration of a measurement unit 6. The brazing unit 5 moves the brazing material core wire unraveled from the brazing material reel (not shown) along the brazing material core wire guide portion 30 by a feed roller (not shown) driven and controlled by the brazing material supply amount control device 9. A brazing material supply nozzle 11 to be sent out, and a crater 12 connected to a gas flow controller 7 for independently controlling the flow rate of each of two systems of propane and oxygen to generate an oxygen-propane flame as a burner flame, The three-axis orthogonal robot 1 is configured to be vertically movable and tiltable on a mounting base 28 attached to a robot attached to a hand (end effector) of the three-axis orthogonal robot 1. The main components of the measuring unit 6 are a radiation thermometer 13 for measuring the surface temperature of the member to be joined, and a CCD camera (photoelectric conversion means) 14 for imaging a mirror-reflected image or the like of a brazing fusion region in the portion to be joined in a reducing atmosphere. And is attached to a mounting base 28 for the robot.

Next, the structure and operation of the brazing unit 5 will be described with reference to FIGS. FIG. 3 is a view of the brazing unit 5 as viewed from the front. Brazing unit 5
Has a configuration in which the brazing material supply nozzle 11 and the crater 12 are attached to a tilt stage 26, and the tilt stage 26 is attached to a brazing unit base 27 via a rotation support mechanism 25. The brazing unit base 27 is mounted on a mounting base 28 for the robot via the linear guide 22, and is configured to be moved up and down by two serially operated air cylinders 23 and 24 connected in series in order to obtain a long stroke. Further, the linear motion air cylinder 21 rotatably supported by the brazing unit base 27 is arranged on the side surface of the brazing unit base 27, and the linear motion output is connected to the tilt stage 26. 4, 5 and 6 show the operation of the brazing unit 5. In FIG. 4, the linear motion air cylinder 2 is set in a state where the linear motion air cylinder 21 is not extended.
3 and 24 show a retreat state in which the linear motion output is extended, the brazing unit base 27 is raised, the brazing material supply nozzle 11 and the crater 12 are retracted together with the tilt stage 26, and brazing is not performed. In FIG. 5, both the linear motion air cylinders 23 and 24 are retracted, the brazing unit base 27 is lowered, the brazing material supply nozzle 11 and the crater 12 are lowered together with the tilt stage 26, and brazing is performed from the horizontal direction. Indicates the status. In FIG. 6, since there is an obstacle, the linear motion air cylinder 21 is extended and
One of the linear motion air cylinders, for example, only the linear motion air cylinder 23 is extended, and the brazing material supply nozzle 11 and the crater 12 are set in a state where the tilt stage 26 is tilted with respect to the brazing unit base 27. This shows a state in which brazing is performed from an obliquely upper position by inclining. That is, FIG. 4 shows that the brazing material supply nozzle 11 and the crater 12 are connected to the member 10 to be joined.
FIG. 5 shows the brazing material supply nozzle 11 and the crater 12 when there is no obstacle.
FIG. 6 shows a state in which the brazing filler metal supply nozzle 11 and the crater 12 are inclined toward the member 10 when there is an obstacle.

Next, a method of attaching the brazing material supply nozzle 11 and its operation will be described with reference to FIG. Brazing material core wire 29
Is supported by L-shaped brackets 35 and 36 attached to the front-rear movement stage 40 slidably back and forth through a metal bush 32. Further, a block 31 is fixed to the brazing material core wire guide portion 30 by split fastening. A tension spring 33 is suspended between the block 31 and the L-shaped bracket 36 so that the brazing material core wire guide 30 is advanced until the block 31 contacts the stopper 34.
A feed roller (not shown) that feeds the brazing material core wire 29 is attached to the brazing material core wire guide portion 30. That is, the brazing material core wire guide portion 30 is
9 is supported by L-shaped brackets 35 and 36 so as to be movable in the thrust direction together with a feed roller (not shown) for feeding the material 9 along the brazing material core wire guide portion 30. The brazing material core wire 29 released from the reel (not shown) is guided by a brazing material core wire guide portion 30 by a feed roller (not shown) and sent out from the nozzle at the tip, and the tip of the brazing material core wire 29 is joined. When it comes into contact with the member 10, the brazing material core wire guide portion 3 is moved together with the feed roller against the tensile force of the tension spring 33.
0 will retreat. The limit sensor 38 detects that the brazing material core wire guide portion 30 is retracted by a predetermined amount, and as a result, is a sensor for controlling the feed of the brazing material core wire 29. Further, a transmission type sensor 37 for detecting that the brazing material core wire 29 is being fed is disposed at the tip of the brazing material supply nozzle 11. The sensor 37 may be a reflection type sensor or a contact type sensor. As described above, the brazing filler material supply mechanism 41 is mounted on the front-rear movement stage 40. Stage 4 for back and forth movement
Numeral 0 is supported movably back and forth by a guide rail 39 mounted on the tilt stage 26, and is configured to move back and forth by, for example, driving an air cylinder.

The operation of the brazing material supply nozzle 11 is shown in FIG.
Explanation will be made using (b) and (c). At the time of brazing, before supplying the brazing filler metal, an oxygen-propane flame, which is a burner flame, is generated in advance from the crater 12 under the control of the gas flow rate controller 7 so that the parts to be joined in the reducing atmosphere are heated to a temperature at which wettability is good. Perform preheating to raise. As in the present embodiment, after confirming that the temperature of the portion to be joined has risen to a temperature having good wettability by the radiation thermometer 13 or the like, the entire control device 4 issues a command to the brazing material supply amount control device 9. The brazing material supply amount control device 9 controls the brazing material core wire 29 to start supplying to the portion to be joined based on this command. By the way, the member to be joined 10
After preheating, the brazing filler supply controller 9 changes from the state shown in FIG. 7A to the state shown in FIG. 7B based on a command obtained from the entire controller 4 by, for example, driving an air cylinder. The forward / backward movement stage 40 is moved forward along the guide rail 39 in the right direction in the figure to control the brazing material supply mechanism 41 so as to approach the workpiece 10 made of a copper pipe. This movement is to prevent the tip of the nozzle 11 from being conveyed by a conveyor or the like and hitting the workpiece 10 positioned at the brazing position. Therefore, this movement may be performed by the robot mechanism 1.

Thereafter, based on a control command from the brazing material supply amount control device 9, a core wire feeding motor (not shown) is driven to rotate a feed roller (not shown) to rotate the brazing material core wire 2.
9 while being guided by the brazing material core wire guide portion 30.
Send out from the tip of 1. Since the tip of the brazing material core wire 29 does not immediately melt due to the surface temperature of the member to be joined 10 which is a copper pipe, after contact with the member to be joined 10, FIG.
As shown in FIG. 7, the brazing rod core 30 is pushed against the pressure of the tension spring 33 which is relatively weak. Even if the brazing material core wire 29 is continuously fed in this manner, the brazing material core wire guide portion 30 together with a feed roller (not shown) for feeding the brazing material core wire resists the pressure of the relatively weak tension spring 33 in the thrust direction, as shown in the figure. Since it is possible to escape to the left, it is possible to prevent the brazing material core wire 29 from forcibly pushing and deforming the member to be joined 10 and to penetrate the member to be joined 10, thereby forming a gap between the crater 12 and the member to be joined 10. The relative positional relationship can be prevented from shifting,
The occurrence of abnormal heating of the member to be joined 10 due to the burner flame can also be prevented. Further, if the supply of the brazing material core wire 29 by the feed roller (not shown) is stopped after the limit sensor 38 confirms the passage of the block 31, the extra brazing material core wire is melted at the surface temperature of the portion to be joined. Supply of a simple core wire can be prevented. If the brazing material melts out on the contact surface, the brazing material core wire guide portion 30 returns rightward in the drawing together with the feed roller by the tensile force of the tension spring 33. Then, when the limit sensor 38 does not detect the block 31, the core wire feeding motor is driven again to rotate the feed roller, and the feeding of the brazing material core wire 29, that is, the supply is resumed. Thus, the brazing material core wire 29
Since the appropriate supply is always performed in a state against the pressure of the spring 33, the excess supply can be prevented.

According to the embodiment described above, it is possible to solve the problem in the case where the brazing material core wire is supplied while being preheated as described below, as compared with the case where the brazing material core wire is supplied while being preheated. If the brazing core wire is supplied while preheating, if the feed speed of the brazing core wire is too slow, the brazing material will melt away before the brazing core wire reaches the part to be joined, and the feed speed of the brazing core wire If the temperature is too fast, the member to be joined is pushed away by the cooled core wire because the brazing material core wire is not sufficiently heated, and it is very difficult to set and adjust the feed speed of the core wire according to the burner flame. In the present embodiment, the force in the thrust direction by the tension spring 33, that is, the member 1 to be joined of the brazing material core wire 29.
Although the pressing force to zero is controlled, by controlling the pressure of a force sensor or an air cylinder for driving the brazing material supply mechanism 41 itself back and forth by using a pneumatic control device including a pressure detection switch and the like. The pressing force may be kept moderate. Further, in this embodiment, only the backward end is measured by the limit switch 38. However, a method of measuring the accurate position of the block 31 with a linear sensor or the like and appropriately maintaining the relative position with the member 10 to be joined is also possible. good.

Further, when brazing is continuously performed a plurality of times (when a plurality of works are continuously flown or when a plurality of locations are brazed in one work), how much brazing was performed last time. The problem is whether the core wire is actually melted and used. A change in the amount of use means that the amount of protrusion of the core wire from the nozzle after use changes. If the amount of protrusion is short, it takes time until the brazing material is supplied to the members to be joined. In addition, if the length is long, an unnecessarily large amount of brazing material may be supplied, so that it is easy to cause dripping. Therefore, after use, the feed roller is reversed to retreat the brazing material core wire 29 once from the tip of the nozzle 11, and then the feed roller is rotated forward to send the brazing material core wire 29 from the tip of the nozzle 11 and the transmission type sensor 37. By detecting the leading end of the core wire and measuring the feed amount of the brazing core wire 29 by the feed roller from the detected state, it is possible to always keep the protrusion amount of the brazing core wire 29 at the start of brazing constant. Becomes As shown in FIG. 7B, in a state where the block 31 is in contact with the stopper 34, the distance between the transmission sensor 37 and the member 10 is assumed to be constant. If the transmission sensor 37 and the member 10
If the distance between and fluctuates, measure this distance,
It is necessary to control the amount of protrusion of the brazing material core wire 29 according to the measured distance. Further, although the transmission sensor 37 is configured to optically detect the leading end of the core wire, it is also possible to use electromagnetic waves or to detect electrically. It is also possible to detect by a contact method.

Next, the brazing procedure will be described with reference to FIG. First, the copper pipe 10 after fitting, which is a member to be joined,
It is carried into the brazing position manually or automatically. As shown in FIG. 4, the brazing unit 5 and the measuring unit 6 which are raised and retracted under the control of the brazing material supply amount control device 9 are joined to the joined member 10 carried in. Robot control device 3
Are positioned relative to each other using the three-axis orthogonal robot mechanism 1 based on the control from (step 81). Next, the brazing unit 5 is controlled based on the brazing material supply amount control device 9.
5 is lowered to the state shown in FIG. 5 or FIG.
Is preheated in the vicinity of the portion to be joined (step 82). After this,
For example, an initial image signal shown in FIG. 11A obtained from a portion to be joined illuminated by the multi-stage illumination 8 is captured by a CCD camera (photoelectric conversion means) 14 and is provided in an image processing apparatus 4. The initial image signal is stored in the memory (step 83). The surface temperature of the part to be joined (pipe) is measured by the radiation thermometer 13, and the surface temperature of the part to be joined is input to the entire control device 4 (step 84). The overall control device 4 determines whether or not the measured surface temperature of the portion to be joined has reached or exceeded a temperature threshold value (temperature lower limit value) that is a temperature having good wettability (step 85). When it is determined that the surface temperature of the portion to be joined has reached or exceeded a temperature threshold value (lower temperature limit value) that is a temperature having good wettability, a brazing material supply command is issued to the brazing material supply amount control device 9. (Step 86). That is, steps 82 to 85 indicate the range of the time for preheating the portion to be joined.

Next, upon receiving a brazing material supply command from the overall control device 4, the brazing material supply amount control device 9 controls the brazing material supply mechanism 41 as described with reference to FIG.
The brazing material core wire 29 is supplied to the portion to be joined. The image processing device 4 is illuminated by the multi-stage illumination 8 and is sequentially imaged by the CCD camera (photoelectric conversion means) 14 based on the reflected light from the portion to be bonded in the reducing atmosphere.
The image signal shown in (b) is fetched (step 87), and the initial image signal fetched in step 83 is subtracted from the fetched image signal to delete the same, thereby indicating, for example, the melting of the solder shown in FIG. 11 (c). An image signal is obtained, and a wax melting characteristic amount such as a wax melting area is calculated from the obtained image signal indicating the wax melting (step 8).
8), it is determined whether or not the calculated feature amount such as the area has exceeded an allowable value (threshold) (step 89);
When it is determined that the characteristic amount such as the area exceeds the allowable value (threshold), a command to stop the brazing material supply is issued to the brazing material supply amount control device 9 (step 90), and the brazing material supply amount control device 9 is issued. Controls the brazing material supply mechanism 41 to stop the supply of the brazing material core wire 29. Next, the brazing unit 5 is raised and retracted under the control of the brazing material supply amount control device 9 to end the brazing (step 91). That is, steps 86 to 90 show the brazing material supply range by the brazing material supply mechanism 41. Note that the feature amount other than the area includes the distribution or change of the maximum length in the horizontal direction and the height in the vertical direction shown in FIG. It is necessary to set the allowable value so as to correspond to these feature amounts. In short, even if there is variation in the gap amount between the fittings due to the dimensional variation of the parts to be joined, the brazing material is sufficient in the part to be joined, due to the feature amount calculated from the image signal indicating the melting of the brazing shown in FIG. What is necessary is just to be able to confirm that it has been supplied. As described above, the feature amount is calculated by the area because the height in the vertical direction in the brazing fusion region does not vary much, and the horizontal length in the brazing fusion region depends on the supply amount of the brazing material. Is greatly changed.

Next, the detection of the molten solder region according to the present invention will be described in detail with reference to FIGS. The principle of detecting the molten solder region will be described with reference to FIG. In FIG.
2 shows an optical system for detecting a brazing fusion region. A multi-stage illumination 8 using a ring-shaped fluorescent lamp is arranged in the axial direction of a member to be joined 10 made of a copper pipe, and a CCD camera 14 is arranged diagonally above. In brazing or soldering, it is necessary to remove dirt, particularly an oxide film, on the surface to be joined in order to secure the joining strength. For this reason, the oxide film is removed using a flux in the case of solder, and in the case of the present embodiment, a reducing action by phosphorus contained in the brazing material. For this reason, even in the case of soldering, during brazing, the vicinity of the joint is always in a reducing action state, and in particular, the brazing fusion region always has a beautiful mirror surface state. In other words, in the case of brazing, since the oxide film is removed using the reduction action of phosphorus contained in the brazing material, the portion to be joined is in a reducing atmosphere, and especially the brazing fusion region always has a beautiful mirror surface state. I have. That is, the brazing fusion region has an optically high reflectance. In other words, in the image measured by the CCD camera 14, the reflected image brightness in the brazing fusion region is the highest. However, in order to provide a sufficient contrast between the reflection image from the pipe surface and the reflection image from the brazing fusion zone, the multi-stage illumination 8 is arranged in the pipe axis direction, and the pipe step portion which is the brazing fusion zone is more strongly irradiated. Configuration. Since the specular reflection image is mainly a regular reflection image in which the incident angle from the multi-stage illumination 8 is equal to the emission angle of the reflected light, as shown in FIG.
When the angle between the D cameras 14 is 2Θr, the portion of the molten region where the reflected image is obtained is mainly from the surface where the bisector of the angle between the multi-stage illumination 8 and the CCD camera is equal to the radiation of the molten surface. . However, since the brazing fusion surface is a free-form wavefront, the above condition is not satisfied over the entire region of the brazing fusion region, and it only partially shines. Therefore, in order to obtain more reflected images, it is necessary to irradiate from multiple directions. In this embodiment, the multistage illumination 8 is constituted by four ring-shaped fluorescent lamps. As a result, since the vicinity of the joint is in a reducing action state, the wax melting region always has a beautiful mirror surface state, the reflectance β of the mirror surface portion increases, and the emissivity α decreases, and the CCD camera 14
Can be received as a reflected light image B having a high luminance from a brazed region where the brazing material is melted. However, the CCD camera 14 also detects the reflected light due to the burner flame, which may cause erroneous recognition.

Therefore, in the present embodiment, a bandpass filter that transmits only a specific wavelength is mounted on the lens barrel of the CCD camera 14 in order to optically remove the flame. FIG.
0 (a) shows an example of the result of spectroscopic measurement of the flame during brazing. In this case, the components of the flame include an oxygen-propane flame, which is a burner flame, and a flame reaction of copper and phosphorus, which are brazing filler metals. As described above, the wavelength is around 590 nm and 750 nm.
It has strong luminance near nm. The radiant heat component also gradually increases as the wavelength increases from around 600 nm. FIG. 10B shows an example of a bandpass filter transmission characteristic which is a wavelength component captured by the CCD camera 14. This filter is an interference filter formed by vapor deposition, and has a high transmittance in a range from about 400 nm to about 590 nm. By using such a filter, it is possible to measure the state of the surface of the portion to be joined (pipe) without displaying a flame and a radiant heat image in an image captured by the CCD camera 14. Thus, CC
If the D camera 14 receives light in a wavelength range longer than 600 nm, which is a long wavelength side, light components due to a radiation image will also be received, and it may be difficult to distinguish a reflected image. Therefore, the CCD camera 14 is 600 n
If only the light in the wavelength range shorter than m is received, the flame (burner flame and flame color reaction) and the radiant heat image are erased, so that it is possible to detect only the image showing the brazed region, Can be easily separated and identified. If the illumination light illuminated by the multi-stage illumination 8 includes a large amount of light in a wavelength range shorter than 600 nm, a flame (burner) can be used even if the CCD camera 14 does not receive only light in a wavelength range shorter than 600 nm. If the flame and flame color reaction) and the radiant heat image can be reduced, it is possible to separate and identify the brazed molten region.

In order to measure the reflected light in such a limited wavelength range, the light source needs to have a sufficient amount of light in the selected wavelength range. In this embodiment, a fluorescent lamp is used. A discharge tube is known as a light source having a large amount of light, but many types have a light amount only at a limited wavelength, and for example, the same xenon lamp has a selected wavelength whose spectrum changes depending on a high-pressure type or a low-pressure type. Care must be taken because the light quantity cannot always be obtained in the region.
In addition, in the wavelength range of about 600 nm to 750 nm, an inexpensive LED can be applied. However, since the amount of light per LED is small, it is necessary to pay attention to the necessary number for securing a sufficient amount of light. Halogen, which is a kind of incandescent lamp, is one of suitable light sources because it can obtain a large amount of light in a wide wavelength range and can be obtained at low cost. However, since it becomes a point light source, it is desired to use a plurality of multi-directional illuminations in order to obtain a sufficient reflection area from the brazing fusion region.

Next, an embodiment of image processing for processing an image signal picked up by the CCD camera 14 in the image processing apparatus 4 will be described with reference to FIGS. As described above, the CCD camera 14 is used to capture the molten solder region as an image having high brightness.
Is converted into a binary image signal at a predetermined threshold value by converting an image signal having a grayscale value obtained from the image signal or a digital image data having a grayscale value obtained by A / D conversion of this image signal, to separate a brazed molten region. . However, in many cases, the background image also has a high-luminance portion, which is likely to cause erroneous recognition. Therefore, the image processing device 4 fetches in advance an initial image before the brazing filler is added as shown in step 83 in FIG. 8 (FIG. 11A), and in FIG.
As shown in FIG. 7, a difference image process for obtaining a luminance difference from the captured image at the time of measurement (FIG. 11B) is performed, and a binarization process is performed on the difference image signal with a predetermined threshold (FIG. 11). (C)).
As a result, the image processing device 4 can remove the unchanged background image and extract only the changed image after adding the brazing filler metal, thereby avoiding erroneous recognition.

Further, the processing device 4 for images etc.
The area in the brazing fusion region is calculated by calculating the area of the bright portion after binarization shown in (c), and when the calculated area reaches a preset allowable value (threshold). Check that sufficient brazing material has been supplied to the parts to be joined. For this reason, there is no lack of brazing at the portion to be joined.

In the above-described embodiment, the characteristic amount represented by the area in the brazing fusion region is calculated. However, it is not always necessary to calculate the characteristic amount represented by the area. What is necessary is just to be able to confirm that it has been supplied to. That is, the maximum length in the horizontal direction shown in FIG. 11 (c) indicates that the brazing material has spread to the portion to be joined, and the height in the vertical direction indicates a rather molten state. The feature amount represented by the distribution or change of the maximum length in the horizontal direction and the height in the vertical direction (a maximum value, a minimum value, an average value, or the like of heights can be considered as an index indicating the distribution or change) is calculated. However, if it is determined whether or not the tolerance set for each is satisfied, it can be confirmed with high accuracy that a sufficient amount of brazing material has been supplied to the portion to be joined. The reason for calculating the feature value by the area is that the height in the vertical direction in the brazing fusion region does not change much, and the horizontal length in the brazing region varies greatly depending on the supply amount of the brazing material. It is based on

The image processing device 4 is connected to display means 4 such as a connected display in order to increase the processing speed.
The image signal captured and captured by the CCD camera 14 is displayed on a, and a window is set in the vicinity of the portion to be joined using the input means 4b including a mouse, a keyboard, and the like with respect to the displayed image signal. It is also effective to perform image processing only on the set window range. In this case, FIG.
If the window is set just before the connection as shown in FIG. 2A, it contributes to the hanging area below the connection portion shown in FIG. 12B and the actual connection shown in FIG. It can be separated into a braze joint area. in this case,
The image processing device 4 may evaluate the area of only the brazing joint region as the brazing fusion area. This process is repeated until the area exceeds a preset allowable value (threshold value), and the brazing material supply amount controller 9 is instructed to continue to supply the brazing material core wire 29 by the brazing material supply mechanism 41. Put out. The image processing device 4 issues a command to stop the brazing material supply to the brazing material supply amount control device 9 when the allowable value (threshold value) is exceeded, and the brazing material supply mechanism 41 The supply is stopped, and the brazing material supply mechanism 41 is stopped.
Is lifted up and the brazing is completed.

FIG. 13 shows an example of a time-series change in the melted area calculated by the processing device 4 for images and the like. The brazing melting area gradually increases from the start of the brazing material supply, and the brazing material supply is stopped when the area exceeds the allowable value. Conventionally, the supply of the brazing material core wire has been controlled by a supply time set in advance, that is, a fixed amount of supply has been performed. However, when the supply amount of the brazing material differs due to variation in the gap amount between fittings due to dimensional variation of the parts to be joined, or dripping, brazing shortage occurs. However, according to the present embodiment, since the degree of rotation of the brazing is directly measured, the brazing material is continuously supplied until it is confirmed that sufficient brazing has been supplied to the portion to be joined. Absent.

[0033]

According to the present invention, since it is possible to directly measure how the brazing material is actually supplied to the portion to be joined, it is possible to control the supply amount of the brazing material, and as a result, This has the effect of improving the reliability of brazing at the joint.

Further, according to the present invention, it is possible to automate a brazing process requiring a high degree of skill, and to promote a labor-saving and rationalization.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a configuration of an embodiment of an automatic brazing apparatus for performing an automatic brazing method according to the present invention.

FIG. 2 is a perspective view showing a specific embodiment of a brazing unit and a measuring unit shown in FIG.

FIG. 3 is a front view of a brazing unit and a measuring unit shown in FIG. 2;

FIG. 4 is an operation explanatory view of the brazing unit shown in FIGS. 2 and 3, showing a state where the brazing unit is raised and retracted;

FIG. 5 is an operation explanatory view of the brazing unit shown in FIGS. 2 and 3, showing a state in which the brazing unit is lowered to face a portion to be joined;

FIG. 6 is an explanatory view of the operation of the brazing unit shown in FIGS. 2 and 3, showing a state in which the brazing unit is tilted to face a portion to be joined;

FIG. 7 is a view for explaining the operation of the brazing material supply mechanism according to the embodiment of the present invention.

FIG. 8 is a flowchart for explaining a brazing operation according to the present invention.

FIG. 9 is a principle diagram showing an optical system for detecting a brazed fusion region according to the present invention.

FIG. 10 is a diagram showing the results of flame spectrum spectrometry.

FIG. 11 is a diagram for explaining a background-removed image processing method.

FIG. 12 is a diagram for explaining a method of separating a droop and a bonding region.

FIG. 13 is a diagram showing a time-series change of an area indicating a brazing fusion region according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 3-axis orthogonal robot, 2 ... stand, 3 ... Robot control device, 4 ... Image processing device and whole control device, 5 ... Brazing unit, 6 ... Measuring unit, 7 ... Gas flow controller, 8 ... Multi-stage lighting, 10: work to be brazed (member to be joined), 11: brazing material supply nozzle, 12: crater, 13 ...
Radiation thermometer, 14 CCD camera (photoelectric conversion means), 2
DESCRIPTION OF SYMBOLS 1 ... Linear air cylinder, 22 ... Linear guide, 23 ... Linear cylinder, 24 ... Linear cylinder, 26 ... Tilt stage, 27 ... Brazing unit base, 28 ... Mounting base, 30 ... Brazing material core wire guide part, 31 … Block, 3
2: Metal bush, 33: Tension spring, 34: Stopper, 35: L-shaped bracket, 36: L-shaped bracket, 37: Through-beam sensor, 38: Limit sensor, 40: Stage for moving back and forth

Continuing on the front page (72) Inventor Yoshikazu Suda 800, Tomita, Ohira-cho, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture Inside the Cooling and Thermal Engineering Division of Hitachi, Ltd. Hitachi, Ltd.

Claims (12)

[Claims] A heating means heats the vicinity of a portion to be welded between members to be welded, and measures by a temperature measuring means that a surface temperature of the heated portion to be heated reaches a desired temperature. The joining material is sent to the joining portion based on the above, and the tip of the joining material is pressed against the joining portion in a reducing action state with a desired force to melt the joining material by the surface temperature of the joining portion, and By irradiating light to the part to be joined in the reducing action state, the image by the mirror reflection light from the bonding material melting area is received by the photoelectric conversion means and converted into an image signal, and based on the converted image signal, the bonding material is used. Calculating the characteristic amount indicating the melting region, when the calculated characteristic amount reaches the allowable value, stop sending the joining material to the joined portion, and then retract the joining material from the joined portion. Characteristic joining method. And a heating means for heating the vicinity of the portion to be welded between the members to be welded, and measuring by a temperature measuring means that the surface temperature of the heated portion to be heated reaches a desired temperature. The joining material is sent to the joining portion based on the above, and the tip of the joining material is pressed against the joining portion in a reducing action state with a desired force to melt the joining material by the surface temperature of the joining portion, and The part to be joined in a reducing action state is irradiated with light to block light components due to radiant heat obtained from the part to be joined, and an image by mirror-reflected light from a fusion region of the joining material is received by the photoelectric conversion means, and an image signal is received. Is calculated based on the converted image signal, and calculates a characteristic amount indicating the fusion region of the bonding material. When the calculated characteristic amount reaches an allowable value, the feeding of the bonding material to the portion to be bonded is stopped. , Then before the bonding material Joining method characterized by retracting from the welded portion. 3. The joining method according to claim 1, wherein the joining material is a solder material. 4. The joining method according to claim 1, wherein the joining material is a brazing material. 5. A heating means for heating the vicinity of the portion to be joined between the members to be joined, supplying the joining material to the portion to be joined in a reducing action state, and melting the joining material by the surface temperature of the portion to be joined. By irradiating light to the part to be joined in the reducing action state, the image by the mirror reflection light from the bonding material melting area is received by the photoelectric conversion means and converted into an image signal, and based on the converted image signal, the bonding material is used. A joining method comprising: calculating a feature amount indicating a fusion region; and stopping the supply of the joining material to a portion to be joined when the calculated feature amount reaches an allowable value. 6. Heating the vicinity of the portion to be joined between the members to be joined by a heating means, supplying the joining material to the portion to be joined in a reducing state, and melting the joining material by the surface temperature of the portion to be joined. The part to be joined in a reducing action state is irradiated with light to block light components due to radiant heat obtained from the part to be joined, and an image by mirror-reflected light from a fusion region of the joining material is received by the photoelectric conversion means, and an image signal is received. Is calculated based on the converted image signal, and when the calculated characteristic amount reaches an allowable value, the supply of the bonding material to the portion to be bonded is stopped. A joining method characterized by the above-mentioned. 7. A portion near the portion to be welded between the members to be welded is heated by a burner flame, and the temperature of the heated surface of the portion to be welded is measured to be a desired temperature by temperature measuring means. The brazing material is fed to the portion to be joined based on the above, and the tip of the brazing material is pressed against the portion to be joined in the reducing atmosphere with a desired force to melt the brazing material by the surface temperature of the portion to be joined, By irradiating light to the joints in the reducing atmosphere, the image by the mirror reflection light from the brazing material melting region is received by the photoelectric conversion means and converted into an image signal, and based on the converted image signal, the brazing material is used. Calculating the characteristic amount indicating the melting region, when the calculated characteristic amount reaches the allowable value, stop sending the brazing material to the joined portion, and then retract the brazing material from the joined portion. Characteristic joining method. 8. A portion near the portion to be welded between the members to be welded is heated by a burner flame, and the temperature of the heated surface of the portion to be welded is measured to be a desired temperature by temperature measuring means. The brazing material is fed to the portion to be joined based on the above, and the tip of the brazing material is pressed against the portion to be joined in the reducing atmosphere with a desired force to melt the brazing material by the surface temperature of the portion to be joined, By irradiating light to the part to be joined in the reducing atmosphere, light components due to the burner flame and light components due to the flame color reaction of the brazing material obtained from the part to be joined are shielded by the mirror reflection light from the brazing material melting region. The image is received by the photoelectric conversion means and converted into an image signal, and a feature amount indicating the brazing material melting region is calculated based on the converted image signal,
A brazing method characterized in that when the calculated feature value reaches an allowable value, the feeding of the brazing material to the joint is stopped, and then the brazing material is retracted from the joint. 9. The vicinity of a portion to be welded between the members to be welded is heated by a burner flame, and the temperature of the heated surface of the portion to be welded is measured to be a desired temperature by temperature measuring means. The brazing material is fed to the portion to be joined based on the above, and the tip of the brazing material is pressed against the portion to be joined in the reducing atmosphere with a desired force to melt the brazing material by the surface temperature of the portion to be joined, By irradiating light to the part to be joined in the reducing atmosphere, the light component due to the burner flame and the light component due to the flame color reaction of the brazing material and the light component due to radiant heat obtained from the part to be joined are shielded from the brazing material melting region. The image by the specular reflection light is received by the photoelectric conversion means and converted into an image signal, and a characteristic amount indicating the brazing material melting region is calculated based on the converted image signal, and the calculated characteristic amount is an allowable value. Before reaching Brazing method characterized by stop feeding of the brazing material to the joints, it is then retracted the brazing material from the bonding portion. 10. A portion near the portion to be welded between the members to be welded is heated by a burner flame, the brazing material is supplied to the portion to be welded in a reducing atmosphere, and the brazing material is melted by the surface temperature of the portion to be welded. By irradiating light to the joints in the reducing atmosphere, the image by the mirror reflection light from the brazing material melting region is received by the photoelectric conversion means and converted into an image signal, and based on the converted image signal, the brazing material is used. Calculate the characteristic amount indicating the melting area,
When the calculated feature value reaches an allowable value, the supply of the brazing material to the portion to be joined is stopped. 11. A portion near the portion to be joined between the members to be joined is heated by a burner flame, and the brazing material is supplied to the portion to be joined in a reducing atmosphere to melt the brazing material by the surface temperature of the portion to be joined. By irradiating light to the part to be joined in the reducing atmosphere, light components due to the burner flame and light components due to the flame color reaction of the brazing material obtained from the part to be joined are shielded by the mirror reflection light from the brazing material melting region. The image is received by the photoelectric conversion means and converted into an image signal, and a characteristic amount indicating the brazing material melting region is calculated based on the converted image signal. When the calculated characteristic amount reaches an allowable value, the soldering is performed. A brazing method characterized by stopping supply of a material to a portion to be joined. 12. A portion near the portion to be welded between the members to be welded is heated by a burner flame, the brazing material is supplied to the portion to be welded in a reducing atmosphere, and the brazing material is melted by the surface temperature of the portion to be welded. By irradiating light to the part to be joined in the reducing atmosphere, the light component due to the burner flame and the light component due to the flame color reaction of the brazing material and the light component due to radiant heat obtained from the part to be joined are shielded from the brazing material melting region. The image by the specular reflection light is received by the photoelectric conversion means and converted into an image signal, and a characteristic amount indicating the brazing material melting region is calculated based on the converted image signal, and the calculated characteristic amount is an allowable value. The supply of the brazing material to the portion to be joined is stopped when the temperature of the brazing material is reached.